1. Technical Field
The present invention relates to an authentication method, authentication system, in-vehicle device, and authentication apparatus.
2. Background Art
Car navigation systems have become widely used in recent years, and it has become common that automobiles are equipped with in-vehicle devices which can play music and video, and display navigation information, for example. In addition, the in-vehicle devices have come to communicate with portable terminal devices such as a portable telephone and a Personal Digital Assistant (PDA) carried by a passenger, and data communication is performed between the portable terminal device and the in-vehicle device.
For communication devices which perform communication with each other, radio communication standard called Bluetooth (registered trademark) is well known. Bluetooth (registered trademark) is a radio communication standard using frequency band of 2.4 GHz, and realizes radio communication within approximately a few-tens-meters-radius range. When communication starts, the communication devices exchange same authentication key called Personal Identity Number (PIN) code, for example, to authenticate the counterpart device. Such authentication process performed at the beginning of the communication is called “pairing” of the communication devices.
In the pairing: an in-vehicle device displays a PIN code on a display device; a user manually inputs the displayed PIN code into a portable terminal device; the portable terminal device transmits the manually-input PIN code to the in-vehicle device.
Manual input of the PIN code, however, is cumbersome for the user. Hence, various attempts have been made to eliminate the input of PIN code and to improve the usability. For example, Patent Document 1 discloses a technology, according to which an infrared communication unit is formed separately from a Bluetooth (registered trademark) communication unit and arranged in each communication device; when a user performs a switching operation, the PIN code is exchanged via the infrared communication unit.
Further, being widespread is a technology for performing user authentication for enhancing security of devices such as an unlocking control device of doors of a vehicle, and an in-vehicle control device such as a car audio system. For example, as user authentication methods for controlling door lock/unlock, smart entry technique which utilizes an immobilizer (i.e., electronic mobile lock device) that performs authentication based on an ID (IDentifier) code specific to a transponder (i.e., electronic chip) and a method using a portable terminal such as a portable telephone are known. Unlike security of normal data communication, it is desirable that security of devices which user uses everyday, such as an in-vehicle control device, be secured through user authentication through simple operation.
For example, Patent Document 2 listed below discloses an anti-theft device for in-vehicle electronic devices. The anti-theft device includes a vehicle antitheft device which permits the use of a car audio system based on an identical ID code as used for an immobilizer to prevent the theft of a car audio system without the need of complicated operation by the user. Further, Patent Document 3 listed below discloses a technology, according to which the user transmits user data using a portable telephone and is allowed to use an in-vehicle electronic device when the user data matches. Further, Patent Document 4 listed below discloses a vehicle antitheft system in which the telephone number of a mobile terminal of an authenticated user is registered in advance, and an antitheft function is activated when power is turned on while a mobile terminal is not connected to a connector of a control device or while a mobile terminal whose telephone number is not registered is connected to the connector of the control device.
Patent Document 1: Japanese Patent Application Laid-open No. 2002-73565
Patent Document 2: Japanese Patent Application Laid-open No. 2000-71893
Patent Document 3: Japanese Patent Application Laid-open No. 2002-205604
Patent Document 4: Japanese Patent Application Laid-open No. 2002-220029